Applicant successfully developed an endless loop cassette and obtained a U. S. Patent on his development, U. S. Letters Pat. No. 3,938,752. This patent issued in 1976. The patented cassette employed a platen having an inverted conical hub mounted on the top thereon which is joined to turn with the platen on which a spool of an endless loop of magnetic tape was placed. This arrangement allows an operating loop of the magnetic tape to be pulled from a point contiguous to the top of the hub to rotate it without binding which binding would ordinarily prevent the transport of an operating tape spool without some type of auxiliary drive for the rotating this assembly as taught in the aforementioned patent.
Applicant has now developed an improved cassette which may be referred to a short or single song cassette employing an endless loop of magnetic tape for Sony Walkman .RTM. players, and like devices. Typically the novel cassette employs 200 feet of less of magnetic tape in the spool on the platen. It is designed to avoid damage to the operating tape loop which will likely result if the loop is transported in the wrong or the undesired direction thereby preventing the spool from rewinding on the platen.
The objective is achieved by special guide means arranged to route the operating tape loop from the endless magnetic tape spool mounted on a platen with the conical hub so the loop will by-pass one of the capstan drive apertures in the novel cassette in which a capstan drive could transport the loop in the wrong direction. It is also a feature of the guide means the align the operating loop between the top and bottom halves of the cassette s it will properly engage the play head of a cassette recorder in which the cassette is used. Preferably the guide means includes a roller member arranged to allow the operating tape loop to pass behind one of the capstan drive apertures and around the roller member to reduce the frictional drag. This arrangement facilitates the transport of longer spools of endless magnetic tape in the novel cassette. The frictional loads are reduced sufficiently with the roller member to prevent binding of the operating tape loop as it exits from the top of the hub, rotating the hub, platen and spool of tape which otherwise might prevent smooth transport of the tape.
In a preferred embodiment, the roller member is mounted on a pivoted arm which allows the roller member to be repositioned in the novel cassette so the operating tape loop can be erased by the normally by-passed erase head when desired by the user. This feature is accomplished by using a two-position arm to reposition the roller member from a first position which by-passes one of the capstan drive apertures to a second position which does not allow the tape to by-pass this capstan aperture so the erase head can engage the operating tape loop threaded across the inside front edge of the cassette.